Madou (魔導) is one of Xavier's four apostles, but his true name is Genbu (玄武). He is sealed within Kobayakawa Chinu. It is implied that he has some kind of connection to Shinobu. He's also the owner of the Genbu Castle.

He's a large faced priest-type man, he appears alongside Xavier when the Demon Army is formed in JAPAN. Generally, he doesn't fight himself, he just observes and manages the troops. He strategizes with Xavier, proposing multiple ways on how to destroy the JAPANese.

He stutters over his words, and appears to not like violence, only killing people when he claims he is helping them or when he has no choice.

His true form, Genbu, appears to be an elephant-like creature with the top of his body covered in stone, and his trunk being a snake.

His most notable feat is his creation Genbu Castle, an interdenominational space where the normal laws of physics don't apply.

He was eventually killed by Rance and his forces in South Africa, JAPAN. He tried stopping Rance from getting near the Soul Binder and Kurohime, but got defeated in his Madou form and his Genbu form.

He's also the only one that can be left alive by the player, although he's still dead in canon.

Genbu is the japanese name for the Black Tortoise, which is one of the Four Symbols of the Chinese constellations. It is usually depicted as a turtle entwined together with a snake, very similar to Genbu's true form.

While he does not physically appear he can be considered one of the main antagonists of Rance 5D since he created Genbu Castle and is indirectly responsible for pretty much every event in the game from Rizna's suffering to Dark Rance's conception.